StellaLyra · 6-inch f/9 M-CRF Ritchey–Chrétien
A closer view of smaller deep-sky targets.
The StellaLyra 6-inch RC combines a 153mm aperture and 1370mm focal length in a short metal tube. Its two hyperbolic mirrors form a Ritchey–Chrétien optical system, with a fixed primary mirror and a separate rear focuser.
Choose it when you want a tighter camera view of smaller targets and are ready to build a tracking, focusing and alignment routine around a longer focal length.
Choose it for framing, not simply more magnification.
With the same sensor, a longer focal length places a smaller area of sky in the image. That can help when a galaxy or compact nebula looks too small in your current wide-field setup.
Check your favourite targets in a field-of-view planner using your actual camera. Some will fit well; larger subjects may need a mosaic. Consider your camera’s pixel size and local seeing alongside the framing, because a closer image scale also makes tracking and focus errors more noticeable.
An RC optical system, with internal baffling.
The design corrects coma without the Newtonian-style coma corrector used by the f/4 and f/5 reflector range. Internal baffles help control stray light.
That does not guarantee a perfectly flat, corrected image across every sensor. Assess the camera and any RC-compatible field-correction optics together. A corrector bought for a Newtonian should not be assumed suitable simply because its barrel fits the focuser.
Focus at the rear while the primary stays fixed.
The 2-inch dual-speed rotatable Crayford focuser moves the camera or eyepiece to focus. The primary mirror remains fixed, avoiding the focusing movement of the primary used in some other telescope designs.
Use coarse adjustment to approach focus, then refine it with the fine control and short test exposures. Support your camera while attaching it and check that the complete assembly remains secure as the telescope points higher in the sky.
Three extension rings help position your imaging train.
Two 25mm rings and one 50mm ring are supplied. Select the combination needed for your particular camera arrangement; do not assume every ring must be installed.
These rings provide mechanical extension. If you add a reducer or flattener, its required distance to the camera sensor is a separate measurement. Account for the camera’s sensor recess, filter hardware and adapters, then check that the complete setup can reach focus with useful adjustment remaining.
Short tube, with rear-mounted equipment to balance.
The published tube length is 391mm and diameter is 193mm including end rings. Weight with the supplied accessories is 5.61kg, and a Vixen-style rail provides the mounting connection.
The camera and extensions add length and weight behind the tube. Balance with the actual imaging train fitted, check saddle travel and verify clearance around the mount. Include guiding equipment, filters and cabling when assessing the complete load.
Plan tracking and alignment as carefully as the optics.
A compact tube does not make long-focal-length imaging insensitive to mount performance. Choose the tracking and guiding arrangement for the image scale and exposure times you intend to use.
Check collimation with a method appropriate to an RC, then inspect a star field before starting a long sequence. If alignment is already good, avoid making unnecessary adjustments. Keep notes and change one factor at a time when investigating uneven stars, so focus, tilt and alignment are not confused with one another.
What is supplied?
| Included | Choose separately |
|---|---|
| RC optical tube with fitted focuser and Vixen-style rail | Tracking mount and tripod or pier |
| 2-inch to 1.25-inch adapter | Camera and suitable camera connections |
| Two 25mm and one 50mm extension rings | Any reducer or field-correction optics |
| Vixen/Synta-style finder base | Finder, guiding equipment and power as required |
A finder is not included. Eyepieces and any diagonal for visual use are also separate purchases.
Specifications
| Optical design | Ritchey–Chrétien, hyperbolic primary and secondary |
|---|---|
| Aperture / focal length | 153mm / 1370mm |
| Focal ratio | Nominal f/9 |
| Focusing | Fixed primary; 2-inch dual-speed rotatable Crayford |
| Tube length / outside diameter | 391mm / 193mm including end rings |
| Weight with included accessories | 5.61kg |
Before choosing the 6-inch RC
Is a reducer included?
No. Select an RC-compatible reducer separately if it suits your camera and target framing. Check the specified spacing and supported sensor size before assembling the imaging train.
Can I use my existing Newtonian coma corrector?
Do not assume compatibility. The RC has a different optical design and does not require a Newtonian coma corrector. Tell us the exact accessory and camera models so the proposed combination can be checked.
Can I observe through an eyepiece?
Yes, with the appropriate eyepiece and focus arrangement. If visual observing is your main priority, compare the complete mounting and accessory requirements with the Dobsonian and Classical Cassegrain ranges before deciding.
Availability reflects supplier stock and can change. Contact Dark Clear Skies to confirm dispatch timing if you need the telescope for a particular date.